1. Field of the Invention
The present invention generally relates to a correction method of a display and a device thereof. More particularly, the present invention relates to a brightness correction method of a plasma display panel and a device thereof.
2. Description of Related Art
In general, the conventional display device may be classified into two types, namely, cathode ray tube (CRT) display and flat panel display. Recently, since the flat panel display is lighter and thinner than the CRT display, and the image displayed by the flat panel display is not influenced by the magnetic field. Therefore, the conventional CRT display has been gradually replaced by the flat panel display and has become the major trend of the display.
In general, the conventional flat panel display includes a liquid crystal display (LCD) and plasma display panel (PDP). The size of the display screen of the PDP may be larger than that of the LCD. Therefore, the PDP occupies a specific market. In general, under the influence of the discharge characteristic of PDP and the light emitting characteristic of the fluorescent luminary of PDP, the relationship between the brightness displayed by each pixel and the sustained light emitting pulse is not linear. Therefore, the difference between the ideal displaying brightness and actual displaying brightness of the data of the gray scale causes a brightness error. Conventionally, a brightness adjustment device and method of adjusting the brightness error for PDP is disclosed in Taiwan Patent Publication No. 582006 by ChungHwa Picture Tubes, LTD. Hereinafter, the patent will be briefly described referring to FIG. 1.
FIG. 1 is a schematic block diagram of a conventional brightness correction device of a PDP. As shown in FIG. 1, the brightness adjustment device 100 of the PDP includes an inverted γ conversion searching unit 110, a gray scale disposal searching correction unit 130 and an error diffusion unit 120. The error diffusion unit 120 includes a first add circuit 121, a brightness error searching circuit 122, a second add circuit 123 and a weighted error circuit 124. The inverted γ conversion searching unit 110 is adopted for receiving an input signal S, wherein the input signal S may includes red, green or blue input signal. Thereafter, the input signal S is converted into a first gray scale data output according to an inverted γ conversion principle.
The first add circuit 121 is adopted for receiving the first gray scale data, and calculating a sum of the first gray scale data and a weighted value of a displaying brightness error of the pixel(s) adjacent to the currently displaying pixel, and then to output a second gray scale data. Wherein, the calculation described above is applied for compensating and revising the displaying error value of the pixel(s) adjacent to the presently displaying pixel by using brightness error diffusion method, therefore the brightness of the frame is more close to the ideal value.
The brightness error searching circuit 122 connected to the first add circuit 121 is adopted for receiving numerical part of the second gray scale, and for searching a given brightness error table to obtain the brightness error value of the presently displaying pixel. The second add circuit 123 is adopted for calculating a decimal error generated by the inverted γ conversion searching unit 110. In general, the decimal error may be ignored by the gray scale disposal searching unit 130, therefore, the decimal error is added into the calculation of the brightness error value. Thus, the value of the displaying brightness error of the currently displaying image includes the decimal error. The value of the displaying brightness error is stored in the memory device 125 of the weighted error circuit 124. Therefore, the memory device 125 may be adopted store the prior displaying brightness error values of the pixel(s) adjacent to the displaying pixel(s) sequentially, and process the displaying brightness error values by weighted calculation to obtain the weighted displaying brightness error values necessary for the add circuit. Referring to the Taiwan Patent Publication No. 582006, the displaying brightness error values of four pixels adjacent to the presently displaying pixel are processed by a weighted calculation with the weighted values a, b, c, d by the multiplier 126, 127, 128, 129 respectively. FIG. 2 is a schematic view of the display pixel of a conventional PDP. Referring to FIG. 2, the method of selection of the pixel adjacent to the displaying pixel may be described. In FIG. 2, each capital letter represents a position of a pixel. For example, when the displaying pixel is G, the prior displayed pixels A, B, C, and F that are adjacent to the pixel G. FIG. 2 is a schematic view of the display pixel of a conventional PDP. In other words, when the displaying pixel is P, the prior displayed pixels H, I, J and O are selected for the weighted calculation.
The gray scale disposal searching unit 130 connected to the error diffusion unit 120 is adopted for receiving the numerical part of second gray scale, and for searching a given gray scale dispose table to obtain a sustained light emitting number of pulse of the displaying pixel for outputting the same.
Referring to FIG. 1 and FIG. 2, in the brightness correction device of the PDP described above, when the displaying pixel is G, the displaying brightness error values and weighted values of the prior displayed pixels A, B, C/pixel F adjacent to the pixel G in the vertical/horizontal direction are provided for calculating the second gray scale data of the pixel G. It is noted that, the displaying brightness error values of the prior displayed pixels A, B, C adjacent to the displaying pixel G in the vertical direction has already been calculated and stored into the memory device 125 of the weighted error circuit 124. However, at this time, the displaying brightness error values of the prior displayed pixel F adjacent to the presently displaying pixel G in the horizontal direction is still under calculation. Therefore, the second gray scale data of the pixel G cannot be calculated until the calculation of the displaying brightness error value of the pixel F is completed. Accordingly, this method of calculation is time consuming, and thus the operating frequency is reduced.